Organic acid-promoted cobalt oxide oxo catalyst system



NW' 5 1957 c. L. ALDRIDGE ETAL *2,812,356 v ORGANIC ACID-PROMOTED COBALT .OXIDE 0X0 CATALYST SYSTEM Filed Feb. 23, 1955 5 Sheets-Sheet 1 Ec| v. FASCE g BY 7J ATToRNEY Nov. 5, 1957 c. L. ALDRIDGE ETAL 2,812,356

ORGANIC ACID-PROMOTED COBALT oxIDE oxo CATALYST SYSTEM Filed Feb. 23, 1955 5 Sheets-Sheet. 2

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' QP-mulini suLfonlc Acm AT 525m 000m AcmTE 'AT MoL amo, Aem/000m 0x|0E usan EFFECT 0F ACID ADDITION T0 COBALT OXIDE CATALYST FIGURE 2 CLYDE L. ALDRIDCE ECI V. FASCE BY d/ Z716 moRNEY mvENToRs Nov. 5, 1957 c. L. ALDRIDGE x-:TAL 2,812,356

ORGANIC ACID-PROMOTED COBALT oxDE oxc CIITALYST SYSTEM Filed Feb'. 23, 1955 5 Sheets-Sheetl 3 ai coA'LT oxmf t' TEMP.. F. 525 2- conm oxlnE (o-'sum E conm Acme (o-m nu) z conm um (o-zonu) I Y conm uml IZ je. o `I I I I I I I o 2 a 4 5 e 1 IOL RATIO ACETICAGID/CUBALT OXIDE 0XONAT|0II 0F C7 OLEFIIIS EFFECT 0F ADDITION 0F AGETIC AGID T0 GOBALT CATALYSTS FIGURE 5 cuni L. ALoRmcE .Ecl v. FAscE INVENTORS uw# 7117( montan United States Patent O ORGANES ACID-PROMTED COBALT OXIDE X0 CATALYST SYSTEM Clyde Lee Aldridge, Baker, and Egi Victor Fasce, Baton Rouge, La., assignors to Esso Research and Engineering Company, a corporation of Delaware Application February 23, 1955, Serial No. 489,919

11 Claims. (Cl. 26o-604) The present invention relates to the preparation of oxygenated organic compounds by the reaction of carbon monoxide and hydrogen with carbon compounds containing olefinic linkages in the presence of a carbonylation catalyst. More specifically, the present invention relates to catalyst combinations particularly adapted to catalyze this reaction.

It is now well known in the art that oxygenated organic compounds may be synthesized from organic compounds containing olcfinic linkages by a reaction with carbon monoxide and hydrogen in the presence of a catalyst containing metals of the iron group, particularly cobalt, in an essentially three-stage process. In the rst stage, the olefmic material, catalyst and the proper proportions of CO and H2 are reacted to give a product consisting predominantly of aldehydes containing one more carbon atom than the reacted olefin. This oxygenated organic mixture, which contains dissolved in it salts and the carbonyls and molecular complexes of of the metal catalyst, is treated in a second stage to cause removal of soluble metal compounds from the organic material in a catalyst removal zone. The catalyst-free material is then generally hydrogenated to the corresponding alcohols, or may be oxidized to the corresponding acid.

The carbonylation reaction provides a particularly attractive method for preparing valuable primary alcohols which find large markets, particularly as intermediates for plasticizers, detergents and solvents. Amenable to the reaction are long and short chained olefinic compounds, depending upon the type alcohols desired.y

Not only olefins, but most organic compounds possessing at least one non-aromatic carbon-carbon double bond may be reacted by this method. Thus, straight and branch chained olefins and diolefins, such as propylene, butylene, pentene, hexene, heptene, butadiene, pentadiene, styrene, olefin polymers, such as diand tri-isobutylene and hexene and heptene dimers, polypropylene, olefinic fractions from the hydrocarbon synthesis process, thermal or catalytic cracking operations, an other sources of hydrocarbon fractions containing olefins'may be used as starting material, depending upon the nature of the final product desired.

The catalyst in the first stage of the prior art processes is usually added in the form of salts of the catalytically active metal with high molecular fatty acids, such as stearic, oleic, palmitic, naphthenic, etc., acids. Thus, suitable catalysts are, for example, cobalt oleate or naphthenate. These salts are soluble in the liquid olefin feed and may be supplied to the first stage as hydrocarbon solution or dissolved in the olefin feed.

The synthesis gas mixture fed to the first stage may consist of any ratio of H2 to CO, but preferably these gases are present in about equal volumes. The conditions for reacting olefins with H2 and CO vary somewhat in accordance with the nature of the olefin feed, but the reaction is generally conducted at pressures inthe range of about 1500 to 4500 p, s. i. g., and at temperatures in y2,812,356 Patented Nov. 5, 1957 ICC the range of about 150-450 F. The ratio of synthesis gas to olefin feed may vary widely; in general, about 2500 to 15,000 cubic feet of Hz-l-CO per barrel of olefin feed are employed.

At the end of the first stage, when the desired conversion of olens to oxygenated compounds has been effected, the product and unreacted material are generally withdrawn to a catalyst removal Zone where dissolved catalyst is removed from the mixture by thermal treatment in the presence of an inert gas, a vapor, hot water, o1' dilute acid. Thereafter, the aldehydic reaction produce is generally hydrogenated to the corresponding alcohol.

It has been recognized that substantially all forms of cobalt catalyze this reaction, for the active catalytic agent is cobalt hydrocarbonyly inV all probability; this compound is synthesized in situ from the cobalt compound or metal originally introduced. However, it has been preferred to employ the compounds of cobalt that are oil-soluble, such as high molecular weight salts of cobalt, i. e. cobalt oleate or naphthenate. These materials form a homogeneous reaction mixture and have a high reactivity or reaction rate, substantially higher than cobalt metal or oxide, or aqueous solutions of cobalt salts, such as cobalt formate or acetate. However, the use of high molecular weight cobalt carboxylates has certain disadventages. They are expensive to prepare, requiring a variety of processing steps, and also contaminate the final reaction product with the acid or ester corresponding to the carboxylate employed. Furthermore, though the reactivity and reaction rates are high, leading to high olefin conversions, the aldehyde and alcohol selectivity resulting from use of these catalysts is not always satisfactory, and may be somewhat low.

An alternative system is the use of metallic cobalt or slurry of cobalt oxide. These catalytic agents, though they have no residues to contaminate the aldehyde or alcohol product, and though they give a better alcohol selectivity than the oil-soluble cobalt soap, have a very slow reaction rate. This is a very serious defect in continuous operation, for low reaction rates mean low throughput rates.

Still another alternative has been the use of aqueous solutions of water-soluble cobalt salts, such as cobalt acetate. Here also the reaction rates of the aqueous solution lare considerably slower than those of oil-soluble cobalt salts. Furthermore, in order to add an amount of cobalt acetate equivalent to cobalt oleate to provide the desired cobalt concentration of about 0.3 weight percent, about 5-6 volume percent of water (based on l olefin) must be added to the olefin feed. Such a system Liquid Conver- Catalyst System Feed sion, Mol

Rate, Percent v. v. hr.

Cobalt Oleate in Olefln 0.6 Do l.. 2 74 Cobalt Acetate in Water 0. G 72 Do l, 2 54 Thus with the aqueous cobalt acetate catalyst it is necessary to decrease olefin feed rateby almost 50% to achieve a conversion level equivalent to cobalt oleate.

The relative reaction rates of a number of types of cobalt-containing substances at a temperature of 340- 350 F. are listed below:

By means of a suitable surge pump liquid olefin or Oxo product is introduced through lines 14 and 15 into surge vessel 18. The system is so designed that except under Induction Reaction positive action from the surge pump, the pressure in the Catalyst Phe/gvd, lnlz surge vessel is sutliciently low to allow slurry to pass m through the lower check valves 12. Under positive action Cohan 01eme 30 7.8 from the surge pump, the `slurry is forced through the Cobalt acetate solution (47 water in olefin) 20 1.4 Upper Check Valves 20.

cobalt Forml, Basi'g'olldj 5 015 l0 and olefin feed or other organic medium, such as recycle rillferhzo aldehyde productor even alcohol distillation bottoms, is

Cobaltitietaiffjjl: jjjj 4 7 0:5 thus continuously injected into carbonylation reactor 24 through line 22. The slurry which consists of about 0.1

These iiguresshow the great diversity in reaction rates t0 3% lJy Weight of cobalt oxide calculated as cobalt, characterizing various cobalt catalyst systems. The low 15 may he mlecreu er the rute or about 5 ro 20u Pounds Por reaction raies of the cobalt salts sneh as Oxalate, ear, bnrrel of olen, at pressures preferably equal to or slightly bonates, etc., and of the oxide and metal are a direct higher than those prevailing h1 reactor 24- result of the low rate of conversion of these solids to A gas IIllXUrc Comprising H2 and CO in approximately active catalyst, i. e. cobalt hydrocarbonyl. equal Volurhee though 05,*2 Volumes HZ/CO muy be It is an object of thepresent invention to set forth a used 1S suppheufhrough hue 26 und flows concurrently process for preparing aldehydes and 21leohols from Olenns with preheated liquid olefin feed admitted through line employing a catalyst system that provides a reaction rate 28 aud Whh the catalyst elurry- Reactor 24 l5 Prefer' of substantially the same order of magnitude as that of ably operated er pressures or about Z500-3,500 P S- goil soluble catalysts, but which is substantially cheaper aud temperatures of 300%?? Fw ucpendlnuoon the and is not associated with the disadvantages resulting 20 olen feed and other reaction conditions. Liquidfeed from use of such Soluble catalysts rates oi 0.2 to` 2.0 v./v./hour may be employed.

It is a stillfurther object of the present invention to Llquld oni/genoten l'eaCIOIl products Consisting mainly employ cheap and readily available cobalt oxide in die ofv aldehydes, containing c obalt carbonyl in solution, as Olio` reaction and to realize reaction rates substantially Well ee'uhreucred Synthesis gases ere Withdrawn over equivalent to those associated with cobalt oleate. 30 head rhrough une 30 from high Pressure reactor 24 and 1t has now been found that cheap but unreaelive fol-ms thereafter freed from dissolved and suspended cobalt. of Cobalt, and in puriieuiar, ooi-,nil oxide, may be ein Thus, the cobalt contaminated aldehyde product may be ployed in the 0X0 reaction and high reaction rates reul freed of dissolved cobalt'by heating it in the presence of izedl when employed in conjunction with small amounts water or dilute acid, in particular dilute acetic acid, and of cocalaiysts of un acidic nature thereafter hydrogenated to the corresponding alcohol. If

The oo catalyst may be added in any convenient man desired, it may beshighly advantageous to lter the Oxo ner, either with the Oxo entaiyst as a slurry, or separately reactor efliuent prior to or subsequent to decobalting, or as, for example, in the olefin feed or recycle stream. In botha preferred embodiment, cobalt oxideis employed as a The Process of the Present invention may be further slurry, and glacial acetic acid as the co-catalyst. The Illustrated hy the following SPeclhc exemples:

slurry may be injected into the Oxo reactor by any con- Example 1 ventional method of adding a slurry to a system under pressure. Such methods include slurry pumps, injectors, The expemhental procedure consisted m charglhg the surge systems, etc. Oneembodiment of a system suitable olefin, and Solid Catalyst tu a homu at roem temperature for carrying out the present invention is shown diagrambrlugmg the bomb up to 100 P- S' 1' g' Vf'hh 1/1 Synthesis muucaiiy in Figure 1 gas and heating to the desired reaction temperature,

Turning now to Figure l, solid-cobalt oxide of suitable quickly ncreeslng the Synthesis gne Pressure lo 3000 particle size is introduced into mixing chamber 2 through P S 1- 8'-, WlrhdraWlnSamPleS 0f the Product aS Teilchopper 4 tion proceeded (400-500 p. s. i. g. drop) and stopping the olefin feed 01- ()Xo product is added to the mixing 50 run when lnal pressure had decreased to 1000 p. s. i. g. chamber through line 3 such that the slurry contains The lnal Glenn Conversion W33 0f the order 0f 4555% from 2 to 10% solids. Likewise, `glacial acetic acid is in all CHSCS- The Product Samples Were inspected for added. The acetic acid is `added to the extent lw6 mols soluble cobalt content and olefin conversion, and the latter of acid per mol of cobalt oxide, preferably 3 45 mols values used to calculate the average reaction velocity conacid per mol of oxide. By means of the circulation D stant k.

Feed C1 Olehns Cu Olcns Catalyst Cobalt Cobalt Plus Cobal- Plus Cobalt Cobalt Plus Oleate Oxide Aeetic tous Acetlc Oleate Oxide Acctlc Acid Oxide Acid Acid Temperature, F 358 356 301 358 375 351 347 365 Pressure at Start, p. s. i. g 3,000 3,000 3,000 3,000 3,000 3,000 3,000 3,000 Pressure at End. p. s. i. g 1,000 1,000 1,000 1,000 1,000 1.000 3,000 1,000 Percent Olen Conversion 47. 5 48. 5 47 48` 43 52 40. 5 Reaction Constant, KXIO 2 9 0 0. 5 6.9 0.7 6.7 6.0 t) l.3 Relative Catalyst Activity to Cobalt oieate i 0.05 0. 76 0. 0s 0. 75 i 0.22 Inspection of Products:

Percent Soluble Cobalt 0.13 0.001 0.005 0.007 0.002 0.01 C0 iss 173 183 153 ss 0H N 2s 4s s2 52 100 Saponicaton No 9 7 21 17 12 Acid No 0. s i s 3. 4 2. 1

*No reaction after 5 hours.

pump 6, the slurry is circulated through lines 8, 10 and 15 to both the top `and bottom of the mixing chamber. 75 baltous oxide show low activity of 1/5-'l/7 These results show clearly that while cobaltic and co that of cobalt oleate catalyst, the addition of 0.1% by weight on feed of acetic acid to the oxides results in a fold increase in catalyst activity and shorter induction period. A similar order of catalyst activity is noted in both the oxonation of a C7 and the more difiicultly oxonatable C12 olefin.

The effect of acid addition to cobalt oxide catalyst is clearly seen in Figure 2, wherein the reaction velocity constant associated with the addition of various acids, and various mol ratios, is clearly evident. These data show that organic acids in general have some effect; the most notable being shown by acetic acid. Formic acid, on the -other hand, actually was found to inhibit the reaction. This is consonant with the general finding that the first members of homologous series have characteristics different from those of higher members.

It is also noted that the highest rate increase effect is attained, in the case of acetic acid, at about 3-4 mols of acid per mol cobalt oxide used. The commercial cobalt oxide employed in these experiments analyzed about 25% C00 and 75% of the double compound COO-C0203. This material is substantially completely insoluble in glacial acetic acid and even with H2504 is digested with a great deal of di-fiiculty. On a stoichiometric basis, 6 mols of acetic acid would be associated with one mol of the commercial oxide calculated as cobalt acetate. The results, however, show that maximum increases in rates are obtained at an acid/oxide ratio less than this stoichiometric quantity. These considerations would indicate that cobalt acetate is probably not formed in the course of the reaction or, if formed, it is present in an activated state.

To determine whether it is the extent of acidity or degrec of ionization that is responsible for the increase in reaction rate, further experiments were carried out at 325 F. and 3000 p. s. i. g. employing 85% phosphoric acid. No enhancement in activity of the cobalt oxide was observed even after 3 hours. Formic acid also, as has been pointed out, gave no enhancement. This acid also is 10 times stronger than acetic acid. Toluene sulfonic acid, which is also stronger than acetic acid, gave some increase, but not to the extent found with acetic acid.

Not all forms of cobalt may be activated in the manner described, but apparently only oiland water-insoluble forms, such as the cobalt oxides. Thus Figure 3 clearly shows that cobalt metal is unresponsive to the acid treatment, while solid cobalt acetate actually decreased in reaction velocity.

The process of the prese-nt invention may lbe modifie-d in many ways without departing from its spirit. Thus instead of adding the catalyst as a continuous stream, it may be desirable to maintain a fixed bed of Oxo catalyst of low order of catalytic activity in a reactor. The reaction is then initiated and controlled by injecting the co-catalyst into the feed or recycle stream. T'he speed of Ithe reaction is controlled by varying the amount of co-catalyst injected.

An important advantage of the process of the present invention is the cobalt catalyst savings that may be realized, because of increased utilization of active catalyst. Thus it has been found thatby the technique of the present invention, substantially less catalyst need be employed than when the cobalt oleate or even solid cobalt acetate is employed as the catalyst. This is demonstrated in the table below, where the soluble cobalt concentration at equivalent C1 olefin conversion levels was determined for a series of catalyst systems. Initially, 0.2% by weight of cobalt on olefin, calculated as metal, was added to the reactor.

These data clearly show that at equivalent olefin conversions, substantially less cobalt oxide has gone into solution than cobalt oleate or acetate. Since the acid activated cobalt oxide reaches this conversion level at almost the same rate as the cobalt oleate, it is thus evident that the substantial savings in catalyst costs may be realized.

Soluble Cobalt Concentration (Average) at lf0-50% Olefn Con- Catalyst version 350 F. B25-330 F.

Cobalt` Oleate The excess cobalt oxide may be recovered, if desired, in any convenient manner. It may be centrifuged from the aldehyde product, filtered, or advantage may be taken of its magnetic properties by electromagnetic recovery. The separated solid catalyst may be washed free of product and returned to the oxonation stage. The soluble catalyst, on the other hand, is separated from the aldehyde product by thermal treatment in the presence'of dilute acids, water or inert gases all in a manner known per se.

What is claimed is:

1. In the process wherein olefinic compounds are reacted with H2, CO and a cobalt catalyst at elevated temperatures and pressures in a reaction zone to produce an aldehyde product, the improvement which comprises employing as a catalyst in said process an oxide of cobalt promoted with an organic acid having at least two carbon atoms, said organic acid being present in an amount sufficient to substantially increase the reaction rate.

2. The process of claim 1 wherein said acid is glacial acetic acid.

3. The process of claim 1 wherein said acid is added to the extent of 1 to 6 mols per mol of the oxide of cobalt.

4. The process of claim l wherein said oxide is passed to said zone slurried in olefin feed.

5. The process of claim 4 wherein said 4acid is added to said olefin feed.

6. An improved olefin carbonylation process which comprises passing into an olefin carbonylation zone an olefin, CO, H2, 0.1-3.0% by weight of an oxide of cobalt, and l-6 mols of glacial acetic acid per mol of oxide, maintaining temperatures of 15G-450 F. `and pressures of 1500-4500 p. s. i. g. in said zone, and withdrawing an aldehyde product from said zone.

7. The process of claim 6 wherein said oxide is added as a continuous stream into said zone as a slurry in an organic liquid.

8. The process of claim 7 wherein said liquid is olefin feed.

9. The process of claim 8 wherein said acid is added concomitantly with said oxide.

10. The process of claim 9 wherein 34.5 mols of acid per mol of oxide is added to said zone.

11. The process of claim 6 wherein said oxide is maintained as a fixed bed in said carbonylation zone land said carbonylate reaction is controlled responsive to the injection of said acid to said zone.

References Cited in the file of this patent UNITED STATES PATENTS Gresham et al. June 18, 1946 Schreyer Aug. 14, 1951 OTHER, REFERENCES 

1. IN THE PROCESS WHEREIN OLEFINIC COMPOUNDS ARE REACTED WITH H2, CO AND A COBALT CATALYST AT ELEVATED TEMPERATURE AND PRESSURES IN A REACTION ZONE TO PRODUCE AN ALDEHYDE PRODUCT, THE IMPROVEMENT WHICH COMPRISES EMPLOYING AS A CATALYST IN SAID PROCESS AN OXIDE OF COBALT PROMOTED WITH AN ORGANIC ACID HAVING AT LEAST TWO CARBON ATOMS, SAID ORGANIC ACID BEING PRESENT IN AN AMOUNT SUFFICIENT TO SUBSTANTIALLY INCREASE THE REACTION RATE. 